<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        
        var user_input1 = prompt("请输入第一个数字");
        var user_input2 = prompt("请输入第二个数字");
        var num1 = "";
        num1 = user_input1;
        user_input1 = user_input2;
        user_input2 = num1;
        document.write(user_input1,user_input2);
    </script>
</body>
</html>